U.S. patent application number 12/181513 was filed with the patent office on 2010-02-04 for recovering the compression energy in gaseous hydrogen and oxygen generated from high-pressure water electrolysis.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Thomas L. Gibson, Nelson A. Kelly, David B. Ouwerkerk.
Application Number | 20100025232 12/181513 |
Document ID | / |
Family ID | 41528351 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100025232 |
Kind Code |
A1 |
Kelly; Nelson A. ; et
al. |
February 4, 2010 |
RECOVERING THE COMPRESSION ENERGY IN GASEOUS HYDROGEN AND OXYGEN
GENERATED FROM HIGH-PRESSURE WATER ELECTROLYSIS
Abstract
Exemplary embodiments include an apparatus, and method
associated therewith, for recovering the compression energy stored
in hydrogen gas and oxygen gas generated by the electrolysis of
water in a high-pressure water electrolyzer. The restored
compression energy may be recovered and converted to a useable form
to provide power to the high-pressure water electrolyzer, or
alternatively to provide usable power to a coupled system that uses
high-pressure hydrogen gas or oxygen gas such as a fuel cell for an
electric vehicle, or both for use in providing power to the
electrolyzer and to the fuel cell electric vehicle.
Inventors: |
Kelly; Nelson A.; (Sterling
Heights, MI) ; Gibson; Thomas L.; (Utica, MI)
; Ouwerkerk; David B.; (Torrance, CA) |
Correspondence
Address: |
General Motors Corporation;c/o REISING, ETHINGTON, BARNES, KISSELLE, P.C.
P.O. BOX 4390
TROY
MI
48099-4390
US
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
DETROIT
MI
|
Family ID: |
41528351 |
Appl. No.: |
12/181513 |
Filed: |
July 29, 2008 |
Current U.S.
Class: |
204/194 ;
205/343 |
Current CPC
Class: |
C25B 9/05 20210101; H01M
2250/20 20130101; Y02E 60/50 20130101; Y02E 60/36 20130101; H01M
16/003 20130101; C25B 1/04 20130101; C25B 15/00 20130101; Y02T
90/40 20130101 |
Class at
Publication: |
204/194 ;
205/343 |
International
Class: |
C25D 17/00 20060101
C25D017/00; C25B 1/00 20060101 C25B001/00 |
Claims
1. A system comprising: a water electrolyzer including a water
inlet and an oxygen gas outlet; an oxygen gas expansion engine
fluidically coupled to said oxygen gas outlet; and an electrical
generator coupled to said oxygen gas expansion engine and
electrically coupled to said water electrolyzer.
2. The system of claim 1, wherein high-pressure oxygen gas produced
in said water electrolyzer is expanded within said oxygen gas
expansion engine to drive said electrical generator to produce
electricity, said produced electricity thereafter used to aid in
powering said water electrolyzer.
3. The system of claim 1 further comprising an oxygen gas storage
tank fluidically coupled to and between said oxygen gas outlet and
said oxygen gas expansion engine.
4. The system of claim 1 further comprising a hydrogen gas
expansion engine fluidically coupled to a hydrogen gas outlet on
said high-pressure water electrolyzer, said hydrogen gas expansion
engine also being coupled to said electrical generator.
5. The system of claim 4, wherein high-pressure hydrogen gas
produced in said water electrolyzer is expanded within said
hydrogen gas expansion engine to drive said electrical generator to
produce electricity, said produced electricity thereafter used to
aid in powering said water electrolyzer.
6. The system of claim 1 further comprising: a hydrogen gas
expansion engine fluidically coupled to said hydrogen gas outlet;
and a second electrical generator coupled to said hydrogen gas
expansion engine and electrically coupled to said water
electrolyzer.
7. The system of claim 6, wherein high-pressure hydrogen gas
produced in said water electrolyzer is expanded within said
hydrogen gas expansion engine to drive said second electrical
generator to produce electricity, said produced electricity
thereafter used to aid in powering said water electrolyzer.
8. The system of claim 1 further comprising a hydrogen gas storage
tank fluidically coupled to and between said hydrogen gas outlet
and said hydrogen gas expansion engine.
9. The system of claim 8 further comprising: a fuel cell electric
vehicle fluidically coupled to said hydrogen gas storage tank.
10. A system comprising: a water electrolyzer including a water
inlet and a hydrogen gas outlet; a hydrogen gas expansion engine
fluidically coupled to said hydrogen gas outlet; and an electrical
generator coupled to said hydrogen gas expansion engine and
electrically coupled to said water electrolyzer.
11. The system of claim 10, wherein high-pressure hydrogen gas
produced in said water electrolyzer is expanded within said
hydrogen gas expansion engine to drive said electrical generator to
produce electricity, said produced electricity thereafter used to
aid in powering said water electrolyzer.
12. The system of claim 10 further comprising a hydrogen gas
storage tank fluidically coupled to and between said hydrogen gas
outlet and said hydrogen gas expansion engine.
13. The system of claim 10 further comprising: a fuel cell electric
vehicle fluidically coupled to said hydrogen gas storage tank.
14. A system comprising: a water electrolyzer for converting water
to a high-pressure gas; a gas storage tank coupled to said water
electrolyzer; a gas expansion engine fluidically coupled to said
gas storage tank; and an electrical generator coupled to said gas
expansion engine and electrically coupled to said water
electrolyzer, wherein said high-pressure gas produced in said water
electrolyzer is expanded within said gas expansion engine to drive
said electrical generator to produce electricity, said produced
electricity thereafter used to aid in powering said water
electrolyzer.
15. The system of claim 14, wherein said high-pressure gas
comprises high-pressure hydrogen gas and high-pressure oxygen
gas.
16. The system of claim 15, wherein said high-pressure hydrogen gas
exits said water electrolyzer through a hydrogen gas outlet to a
hydrogen gas storage tank, said hydrogen gas storage tank being
coupled to a hydrogen gas expansion engine that is electrically
coupled to said electrical generator, wherein said high-pressure
hydrogen gas is expanded within said hydrogen gas expansion engine
to drive said electrical generator to produce electricity, said
produced electricity thereafter used to aid in powering said water
electrolyzer.
17. The system of claim 15, wherein said high-pressure oxygen gas
exits said water electrolyzer through an oxygen gas outlet to an
oxygen gas storage tank, said oxygen gas storage tank being coupled
to an oxygen gas expansion engine that is electrically coupled to
said electrical generator, wherein said high-pressure oxygen gas is
expanded within said oxygen gas expansion engine to drive said
electrical generator to produce electricity, said produced
electricity thereafter used to aid in powering said water
electrolyzer.
18. The system of claim 16 further comprising: a fuel cell electric
vehicle coupled to said hydrogen gas storage tank, said fuel cell
electric vehicle including a fuel cell hydrogen gas storage tank, a
fuel cell hydrogen gas expansion engine and a fuel cell; wherein
high-pressure hydrogen gas contained within said hydrogen gas
storage tank may be delivered to said fuel cell hydrogen gas
storage tank and expanded with said hydrogen gas expansion engine
to provide a quantity of hydrogen gas to said fuel cell.
19. The system of claim 18, wherein said fuel cell electric vehicle
further comprises an electrical generator coupled to said fuel cell
hydrogen gas expansion engine, wherein said high-pressure hydrogen
gas is expanded within said fuel cell hydrogen gas expansion engine
to drive said fuel cell electrical generator to produce
electricity, said produced electricity thereafter used to aid in
powering said fuel cell electric vehicle.
20. The system of claim 19 further comprising: an electric traction
motor coupled to said fuel cell, said electric traction motor
aiding in propelling said fuel cell electric vehicle.
21. The system of claim 20 further comprising a fuel cell
electrical generator electrically coupled to said electric traction
motor, wherein a portion of said electricity is used to aid in
driving said electric traction motor.
22. The system of claim 18, wherein a portion of the mechanical
energy produced by expanding said high-pressure hydrogen gas within
said fuel cell hydrogen gas expansion engine is used to propel said
fuel cell electric vehicle.
23. A method for partially powering a high-pressure water
electrolyzer, the method comprising: providing a high-pressure
water electrolyzer having a water inlet and a gas outlet; coupling
said gas outlet to a gas expansion engine; coupling said gas
expansion engine to an electrical generator; electrically coupling
said electrical generator to said high-pressure water electrolyzer;
introducing a quantity of water within said high-pressure water
electrolyzer; generating a quantity of high-pressure gas from said
quantity of water within said high-pressure water electrolyzer;
introducing a portion of said high-pressure gas to said gas
expansion engine; and expanding said portion of high-pressure gas
within said gas expansion engine, wherein the expansion of said
high-pressure gas drives said electrical generator to produce
electricity, wherein said electricity is introduced to said
high-pressure water electrolyzer to partially drive said generation
of high-pressure gas from said quantity of water.
24. The method of claim 23, wherein generating a quantity of
high-pressure gas, introducing a portion of high-pressure gas, and
expanding said portion of high-pressure gas comprises: generating a
quantity of high-pressure hydrogen gas from said quantity of water
within said high-pressure water electrolyzer; introducing a portion
of said high-pressure hydrogen gas to a hydrogen gas expansion
engine through a hydrogen gas outlet; and expanding said portion of
said high hydrogen pressure gas within said hydrogen gas expansion
engine, wherein the expansion of said high-pressure hydrogen gas
drives said electrical generator to produce electricity, wherein
said electricity is introduced to said high-pressure water
electrolyzer to partially drive said generation of high-pressure
gas from said quantity of water.
25. The method of claim 24, wherein generating a quantity of
high-pressure gas, introducing a portion of high-pressure gas, and
expanding said portion of high-pressure gas further comprises:
generating a quantity of high-pressure oxygen gas from said
quantity of water within said high-pressure water electrolyzer;
introducing a portion of said high-pressure oxygen gas to an oxygen
gas expansion engine through an oxygen gas outlet; and expanding
said portion of high-pressure oxygen gas within said oxygen gas
expansion engine, wherein the expansion of said high-pressure
oxygen gas drives said electrical generator to produce electricity,
wherein said electricity is introduced to said high-pressure water
electrolyzer to partially drive said generation of high-pressure
gas from said quantity of water.
26. The method of claim 25, wherein said electrical generator
comprises a pair of electrical generators, one of said pair of
electrical generators being coupled to said hydrogen gas expansion
engine and the other of said pair of electrical generators being
coupled to said oxygen gas expansion engine; wherein the expansion
of said high-pressure hydrogen gas drives said one of said pair of
electrical generators to produce electricity, wherein said
electricity is introduced to said high-pressure water electrolyzer
to partially drive said generation of high-pressure gas from said
quantity of water; and wherein the expansion of said high-pressure
oxygen gas drives said other of said pair of electrical generators
to produce electricity, wherein said electricity is introduced to
said high-pressure water electrolyzer to partially drive said
generation of high-pressure gas from said quantity of water.
27. The method of claim 24, wherein generating a quantity of
high-pressure gas, introducing a portion of high-pressure gas, and
expanding said portion of high-pressure gas comprises: generating a
quantity of high-pressure oxygen gas from said quantity of water
within said high-pressure water electrolyzer; introducing a portion
of said high-pressure oxygen gas to said oxygen gas expansion
engine through an oxygen gas outlet; and expanding said portion of
high-pressure oxygen gas within said oxygen gas expansion engine,
wherein the expansion of said high-pressure oxygen gas drives said
electrical generator to produce electricity, wherein said
electricity is introduced to said high-pressure water electrolyzer
to partially drive said generation of high-pressure gas from said
quantity of water.
28. The method of claim 24 further comprising: coupling a
high-pressure hydrogen storage tank between said hydrogen gas
outlet and said hydrogen gas expansion engine.
29. The method of claim 28 further comprising: coupling said
hydrogen gas expansion engine to a fuel cell hydrogen gas storage
tank on a fuel cell electric vehicle having a fuel cell;
introducing a quantity of said high-pressure hydrogen gas from said
high-pressure hydrogen gas storage tank through said hydrogen gas
expansion engine to said fuel cell hydrogen gas storage tank to
achieve a first hydrogen gas pressure within said fuel cell
hydrogen gas storage tank; wherein the introduction of said
quantity of high-pressure hydrogen gas to said fuel cell hydrogen
gas storage tank is accomplished by first expanding said quantity
of high-pressure hydrogen gas within said hydrogen gas expansion
engine, therein driving said electrical generator to produce
electricity, wherein said electricity is introduced to said
high-pressure water electrolyzer to partially drive said generation
of high-pressure gas from said quantity of water.
30. The method of claim 29, further comprising: releasing a first
portion of said quantity of hydrogen gas from said fuel cell
hydrogen gas storage tank to said fuel cell; and substantially
simultaneously introducing a corresponding portion of said
high-pressure hydrogen gas from said high-pressure hydrogen gas
storage tank through said hydrogen gas expansion engine to said
fuel cell hydrogen gas storage tank to maintain said first hydrogen
gas pressure within said fuel cell hydrogen gas storage tank;
wherein the introduction of said corresponding portion of said
high-pressure hydrogen gas to said fuel cell hydrogen gas storage
tank is accomplished by first expanding said corresponding portion
of high-pressure hydrogen gas within said hydrogen gas expansion
engine, therein driving said electrical generator to produce
electricity, wherein said electricity is introduced to said
high-pressure water electrolyzer to partially drive said generation
of high-pressure gas from said quantity of water.
31. The method of claim 30, wherein releasing a first portion of
said quantity of hydrogen gas from said fuel cell hydrogen gas
storage tank to said fuel cell further comprises: expanding said
first portion of said quantity of hydrogen gas within a fuel cell
hydrogen gas expansion engine; and introducing at least a portion
of said first portion of said quantity of hydrogen gas with a
hydrogen gas inlet on said fuel cell.
32. The method of claim 31, wherein the expansion of said first
portion of said hydrogen gas within said fuel cell hydrogen gas
expansion engines drives a fuel cell electrical generator to
produce electricity, wherein said electricity is used to power said
fuel cell electric vehicle.
33. The method of claim 32, wherein said electricity may also be
used to power one or more vehicle components on said fuel cell
electric vehicle.
34. The method of claim 31, wherein the expansion of said first
portion of said hydrogen gas within said fuel cell hydrogen gas
expansion engines is converted to mechanical energy to propel said
fuel cell electric vehicle.
Description
TECHNICAL FIELD
[0001] The field to which the disclosure relates generally to
energy recovery systems and, in particular, to the recovery of
compressive energy generated during a high-pressure water
electrolysis process.
BACKGROUND
[0002] Electrolyzers convert abundant, low-energy content chemicals
into more valuable ones by using electricity to break down
compounds into elements or simpler products. A water electrolyzer
is a system of cells in which each cell contains two electrodes. In
each cell water is oxidized at one electrode (called the cell
anode), to produce oxygen gas, and reduced at the other electrode
(called the cell cathode), to produce hydrogen gas. The
oxidation-reduction reactions are driven by a direct current (DC)
power source. Oxygen and hydrogen are generated in a stoichiometric
ratio--two volume units of hydrogen for every one of oxygen--at a
rate proportional to the applied cell current.
[0003] Water electrolysis appears to be ideally suited to making
and storing hydrogen needed to power fuel cells, including
specifically fuel cell powered electric vehicles. In a
high-pressure water electrolyzer, hydrogen gas can be produced at
sufficiently high-pressures (up to about 10,000 pounds per square
inch, psi) for storage without the need for mechanical compression.
Such systems, however, require significant energy input to drive
the high-pressure electrolysis process. In addition, oxygen that is
generated in this process generally goes unutilized, and is
typically vented to the atmosphere.
SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION
[0004] One exemplary embodiment includes a method and apparatus for
recovering the compression energy stored in hydrogen gas and oxygen
gas generated by the electrolysis of water in a high-pressure water
electrolyzer.
[0005] In one exemplary embodiment, the potential energy in
compressed oxygen gas generated as a by-product of electrolytic
hydrogen production via water electrolysis in a high-pressure
electrolyzer may be used to drive a pneumatic engine. The pneumatic
engine can then drive an electrical generator to produce
electricity, and the electricity generated may be used to partially
power the electrolyzer that originally made the oxygen gas and
hydrogen.
[0006] In another exemplary embodiment, the potential energy in
compressed hydrogen gas may be recovered as expansion energy that
in turn may drive an electrical generator. This electrical energy
may then be used to partially power the high-pressure electrolyzer
that originally made the oxygen and hydrogen gas.
[0007] In a related exemplary embodiment, the potential energy from
both the compressed hydrogen gas and oxygen gas generated within
the high-pressure water electrolyzer may be recovered as expansion
energy that in turn may drive one or more electrical generators.
This electrical energy may then be used to partially power the
high-pressure water electrolyzer that originally made the oxygen
and hydrogen gas.
[0008] In yet another exemplary embodiment, the expansion of
hydrogen gas may also be used aboard a fuel cell electric vehicle.
In this embodiment, the compressed hydrogen gas may be recovered as
expansion energy that in turn may drive a mechanical electrical
generator. This electrical energy may be used to partially power
the fuel cell.
[0009] In still another exemplary embodiment, the expansion energy
of hydrogen gas may be used directly as mechanical energy from a
pneumatic engine to help propel the fuel cell electric vehicle.
[0010] In a further exemplary embodiment, the expansion energy of
hydrogen gas may both be used in a hybrid fuel cell/pneumatic
vehicle as both mechanical energy from a pneumatic engine to help
propel the vehicle and further may be used to drive a mechanical
electrical generator and may be used to power a fuel cell electric
vehicle.
[0011] Other exemplary embodiments of the invention will become
apparent from the detailed description provided hereinafter. It
should be understood that the detailed description and specific
examples, while disclosing exemplary embodiments of the invention,
are intended for purposes of illustration only and are not intended
to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Exemplary embodiments of the invention will become more
fully understood from the detailed description and the accompanying
drawings, wherein:
[0013] FIG. 1 is a schematic flow chart of a system used to
generate high-pressure hydrogen and oxygen gases using a
high-pressure water electrolyzer and using the hydrogen in a fuel
cell electric vehicle or stationary fuel cell with recovery of both
the chemical energy of the hydrogen and the compression energy
stored in the high-pressure gases in accordance with an exemplary
embodiment.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0014] The following description of the embodiment(s) is merely
exemplary (illustrative) in nature and is in no way intended to
limit the invention, its application, or uses.
[0015] Referring now to FIG. 1, a system 10 that may generate
high-pressure hydrogen gas and oxygen gas via high-pressure water
electrolysis is provided in one exemplary embodiment. A portion the
hydrogen gas generated may be used by a fuel cell electric vehicle
11 (or stationary fuel cell) is also illustrated within the
exemplary embodiment.
[0016] The system 10 may include a high-pressure water electrolyzer
12 that may be used to generate high-pressure hydrogen gas and
oxygen gas from water. The electrolyzer 12 may be powered by
electricity from a solar system grid 14 or other conventional
electrical powering devices (not shown).
[0017] By definition, a high-pressure electrolyzer is a water-based
electrolyzer that is capable of producing hydrogen gas and oxygen
gas at pressures up to about 10,000 pounds per square inch. One
example of a conventional high-pressure electrolyzer 12 that may be
utilized in the exemplary embodiment is the Avalance high-pressure
electrolyzer (available from Avalance LLC of Milford, Conn.), which
uses a unipolar alkaline (KOH) electrolyte system with cylindrical
steel electrolysis cells and includes structure for balancing the
hydrogen gas and oxygen gas levels and electrolyte levels to keep
the gases and electrolytes separate, as well as preventing the
mixing of the hydrogen gas and oxygen gas.
[0018] Water may be introduced to the electrolyzer 12 from a
holding tank 16; through the use of a high-pressure pump (not
shown). The water may undergo a oxygen evolution reaction
(oxidation reaction) at the electrolyzer anode (not shown) and may
undergo a hydrogen evolution reaction (reduction reaction) at the
electrolyzer cathode (not shown) according to the general
formula:
H.sub.2O.fwdarw.H.sub.2+1/2O.sub.2
[0019] The high-pressure hydrogen gas 18 and oxygen gas 20 produced
within the electrolyzer 12 may be separately removed under pressure
to a hydrogen gas storage tank 22 and oxygen gas storage tank 24,
respectively. In one exemplary embodiment, the pressure of hydrogen
gas 18 that is removed may approach about 10,000 pounds per square
inch.
[0020] The high-pressure oxygen gas 20 may then be introduced from
the storage tank 24 into an oxygen gas expansion engine 26
(pneumatic engine). The expanding oxygen gas within the oxygen
expansion engine 26 may then drive an electrical generator 28 to
produce electricity, and the electricity generated may be used to
partially power the electrolyzer 12. The expanded gas from the
pneumatic engine 26 may then vented to the atmosphere 30.
[0021] The storage of high-pressure electrolytically-produced
oxygen, along with recovery of the compression energy using a
oxygen gas expansion engine 26 as mechanical energy, followed by
conversion of the mechanical energy into electrical energy, may
increase the efficiency of a solar electrolysis process by
utilizing much of the energy stored in the high-pressure oxygen. It
is estimated that an energy savings of up to about three percent of
the lower heating value (LHV) energy of the hydrogen gas produced
by electrolysis in the electrolyzer 12 may be recovered as
electrical energy by using the compression energy in the stored
oxygen in the exemplary embodiment described herein (10,000 psi of
stored O.sub.2).
[0022] The hydrogen gas 18 generated in the electrolyzer 12 may be
introduced from the hydrogen gas storage tank 22 to a hydrogen gas
expansion engine 32 (pneumatic engine). The expansion of hydrogen
gas within the hydrogen expansion engine 32 may then drive an
electrical generator 36 to produce electricity, and the electricity
generated may be used to power the electrolyzer 12. The expanded
hydrogen gas may then be transferred to a fuel cell electric
vehicle holding tank 40.
[0023] The storage of high-pressure electrolytically-produced
hydrogen, along with recovery of the compression energy using a
hydrogen gas expansion engine 32 as mechanical energy, followed by
conversion of the mechanical energy into electrical energy, may
increase the efficiency of a solar electrolysis process by
utilizing much of the energy stored in the high-pressure hydrogen.
It is estimated that an energy savings of up to about six percent
of the lower heating value (LHV) energy of the hydrogen gas
produced by electrolysis in the electrolyzer 12 may be recovered as
electrical energy by using the compression energy in the stored
hydrogen in the exemplary embodiment described herein (10,000 psi
of stored H.sub.2).
[0024] A fuel cell electric vehicle holding tank 40 for a fuel cell
electric vehicle 11 may also be filled with expanding hydrogen gas
from the hydrogen gas storage tank 22 through the gas expansion
engine 32 until such time as there is an equilibrium state in
hydrogen gas pressure between the hydrogen gas storage tank 22 and
the holding tank 40. This equilibrium state may preferably be tied
to a predetermined hydrogen gas pressure within the holding tank
40, corresponding to a predetermined quantity of hydrogen gas. In
this equilibrium state, there is little conversion of compression
energy to mechanical energy occurring in the hydrogen gas expansion
engine 32. The subsequent release of hydrogen gas from the holding
tank 40 to the fuel cell 54 as described below allows additional
hydrogen gas to be filled from the hydrogen gas storage tank 22
through the engine 32 to maintain the equilibrium state. In the
exemplary embodiment shown herein, the hydrogen gas pressure in the
holding tank 40 may be maintained at about 10,000 psi.
[0025] The holding tank 40 may hold the compressed hydrogen gas on
a vehicle 11 until such time as it is needed in the fuel cell 54 to
generate electric power to propel the vehicle 11 and/or provide
power to a particular vehicle component. When needed, the
compressed hydrogen gas contained in the holding tank 40 may be
expanded within the second hydrogen expansion engine 50 and
released to the fuel cell 54.
[0026] In fuel-cell conversion, the hydrogen gas entering the fuel
cell 54 is reacted with oxygen (which may enter the fuel cell 54
from a storage tank 58 or from an ambient setting), in a
stoichiometric ratio, to produce water and electricity, the latter
of which may be used to power an electric traction motor 62. The
electric traction motor 62 may convert the electrical energy to
mechanical energy to propel the vehicle 11 again as shown in box
60. Additional electrical energy for the electric traction motor 62
may be provided by the pneumatically-powered electrical generator
56.
[0027] The expanding hydrogen gas entering the second hydrogen
expansion engine 50 from the holding tank 40 may also be used to
drive an electrical generator 56 and/or may also be fed, in the
form of mechanical energy, to the wheels of the fuel-cell electric
vehicle to propel the vehicle 11, as shown in box 60.
[0028] Thus, the exemplary embodiment illustrated herein provides a
method and apparatus for increasing the efficiency of the
high-pressure hydrogen generation and utilization process by
recovering and utilizing the compression energy stored in
high-pressure hydrogen gas and oxygen gas in ways to reduce energy
costs associated with their production and end use.
[0029] The above description of embodiments of the invention is
merely exemplary in nature and, thus, variations thereof are not to
be regarded as a departure from the spirit and scope of the
invention.
* * * * *